In geometry, the perpendicular symbol is used to show that two lines are perpendicular lines to eachother. Visually, the symbol is made up of two lines which form a perpendicular angle. Typically the perpendicular symbol is used in an expression like this:
In plain langauge this means that the line defined by the two points and and the other line defined by the two points and are perpendicular to each other.
The symbol for two perpendicular lines is a horizontal line with another line drawn perpendicular to it.
A perpendicular angle is visually denoted by drawing a square at the vertex of the angle. The measured angle is equal to π/2 radians or 90°.
A Perpendicular angle, sometimes also referred to as a square angle, is exactly 90 degrees or PI fourths.